In classical interferometry measurement techniques, measurement dynamic range and accuracy are very limited. High accuracy can be achieved over just a small range of depth.
Moire technique measurements are more suited to measuring objects that are nearly two-dimensional, and require high frequency fringes for both projection and reference, making alignment and phase shifting problematic.
Photogrammetry measurements are very slow and labor intensive, and provide high accuracy measurement for only a sparse set of points on a surface.
Plaster mold techniques are slow, very labor intensive and messy.
A laser scanning technique has had limited success and has been burdened by large and heavy measurement systems.
Therefore, there is a need for a device, system or method that provides high accuracy depth measurements over a large range of depth, that has a reliable calibration procedure for enhancing measurement accuracy, that obtains measurement data for a surface at very high resolution to provide a full three-dimensional surface image, and that quickly performs measurement and data processing tasks.
There is a further need for a projection apparatus that is lightweight, handheld, mobile and versatile for ease in operation.
There is a further need for a projection device, system, or method that does not suffer from coherent light effect problems, that reduces alignment and optical quality requirements, that minimizes phase shifting motion accuracy requirements, that obtains high resolution three-dimensional measurements, and that has high-speed measurement capability.